High Definition Transcranial Direct Current Stimulation (HD-tDCS) for Early Alzheimer's Disease

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation tool that alters cortical excitability and activity via application of weak direct currents.HD-tDCS was administered using the Soterix 1×1 tDCS Low-Intensity Stimulator and the Soterix 4×1 Adapter. The selection of the electrode montage was based on computational models generating simulated current topography using HD Explore, which demonstrated good current distribution in the left dorsolateral prefrontal cortex (DLPFC). For left DLPFC stimulation, the anodal electrode was placed at the F3 position (using the International 10-20 EEG system), and the 4 return electrodes (cathodes) were placed at positions AFz, FCz, F7, and C5 (4-6 cm from the anode). The center position CZ was aligned with the vertex of the head. During anodal DLPFC stimulation, participants received stimulation at 2 mA for 30 minutes, including a 30-second ramp-up period at the start and a 30-second ramp-down period at the end.

Computer-based cognitive training (CCT) is a potentially important tool for individuals at risk of dementia. This trial will employ a computerized multi-domain adaptive training program. This program and training model have been demonstrated to be effective and beneficial in patients with vascular cognitive impairment. In the CCT intervention group, participants will undergo 2 weeks of computerized, multi-domain, adaptive training. The training domains include processing speed, attention, perception, long-term memory, working memory, calculation, executive control, reasoning, and problem-solving. Task rigor varies across domains and determines task grouping. Participants are required to complete 30 minutes of daily training(one session each of six 5-minute tasks).

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation tool that alters cortical excitability and activity via application of weak direct currents.HD-tDCS was administered using the Soterix 1×1 tDCS Low-Intensity Stimulator and the Soterix 4×1 Adapter. The selection of the electrode montage was based on computational models generating simulated current topography using HD Explore, which demonstrated good current distribution in the left dorsolateral prefrontal cortex (DLPFC). For left DLPFC stimulation, the anodal electrode was placed at the F3 position (using the International 10-20 EEG system), and the 4 return electrodes (cathodes) were placed at positions AFz, FCz, F7, and C5 (4-6 cm from the anode). The center position CZ was aligned with the vertex of the head. For sham stimulation, participants received only the initial 30-second ramp-up to 2 mA, after which stimulation was immediately terminated.